Though he’s wearing a precisely tailored black suit, Julian Sands is on occasion about as naked as an actor can be in “A Celebration of Harold Pinter,” the one-man show that opened on Tuesday night at the Irish Repertory Theater, directed by John Malkovich. That happens whenever Mr. Sands has no part to play except Julian Sands, the handsome sometime British movie star and our host for the evening.

At such moments he comes across as diffident, courteous and a bit embarrassed to find himself in our company. Since the W. Scott McLucas Studio Theater is smaller than your average classroom, we may feel vicariously embarrassed ourselves, like a mismatched half of a blind date.

But then Mr. Sands switches gears. And suddenly there is nothing at all ingratiating or uncertain about him. On the contrary, he is abrasively self-assured and often hostile and foul-mouthed. This has the perverse effect of making us feel much more at ease.

Mr. Sands, you see, has assumed the voice of Harold Pinter. And it is to hear that voice that we have all gathered in this tiny space.

Though Pinter, who died in 2008, was probably the most influential dramatist of his generation, we hear very little from or about his plays in the aptly titled “Celebration,” which does indeed have a ritualistic, even churchly aspect. We are asked instead to listen to the lesser-known Pinter the poet and to discern the private person within the artist.

Mr. Sands, best known for a career in films as varied as “A Room With a View” and “Warlock,” had rigorous preparation for the task he undertakes here. In 2005 he was asked to substitute for the ailing Pinter as a reader of the playwright’s poems at a London benefit recital.

His coach for the event? Harold Pinter, who drilled Mr. Sands exactingly (and, it would seem, inflection by inflection, pause by pause) in interpreting his poetry. During the performance, Mr. Sands recalls, he was treated to the unnerving sight of Pinter mouthing the words along with him.

Mr. Sands learned his part well. In “A Celebration” he doesn’t exactly do Pinter the way Robert Morse did Truman Capote, or Hal Holbrook did Mark Twain. But when he reads Pinter’s poems, as well as the odd prose piece, you feel the playwright’s presence.

Or should I say Presence, with a capital P? Or perhaps Presence amended by a word with a capital F. As Mr. Sands demonstrates convincingly throughout the evening, nobody used the ultimate four-letter Anglo-Saxon curse word with the daunting force that Pinter did.

Mr. Sands quotes the critic Irving Wardle’s description of Pinter as “the most visible person I ever met.” Every reminiscence, from Mr. Sands or others, that is mentioned here seems to support that impression. (So, for the record, did my one encounter with Pinter, at a London restaurant five years ago.) And when Mr. Sands slips into a Pinter imitation in the casual narrative woven through the reading, it feels like a thump to the chest.

Reading directly from a well-thumbed-looking copy of Pinter’s “Various Voices,” its pages bristling with blue Post-it notes, Mr. Sands shades into a quieter intensity. This is suitable for a writer who was as romantic as he was belligerent.

The poems span more than half a century and vary in tone and quality. The early lyrical works, written when Pinter was a young actor touring in Ireland, can feel like Yeatsian pastiches from a man who has yet to come into his own voice. And some of his later, expressly political poems about the rich and powerful register as glib, even if their anger feels real. (One, from 2002, speaks of “well-dressed creatures” at lunch, “decanting claret in convenient skulls.”)

Often the most effective pieces are the briefest, including the marvelous, six-line 1975 work that begins “I know the place,” with which Mr. Sands begins the show and then repeats several times. Even shorter, and almost as resonant, is Pinter’s elegy for the cricketer Len Hutton, which in its entirety reads: “I saw Len Hutton in his prime/Another time/another time.”

The death poems — including Pinter’s wry, aggressive ode to the cancer cells that eventually took his life — are all strong and read by Mr. Sands with brute conviction. And there are several stark but pretty love poems to Antonia Fraser, Pinter’s widow. (For the record, there is no mention of Pinter’s earlier marriage to the actress Vivien Merchant or to their son; this appears to be a very authorized show.)

But if the focus is on poetry, “A Celebration” also turns out to celebrate, if indirectly, Pinter as an apostle of the theater. Pinter — who started out as an actor (under the name David Baron) — retained a deep fondness for that profession, Mr. Sands says. It feels right that “A Celebration” has been directed by Mr. Malkovich, a man best known as an actor. For this modest, affecting show embodies the notion of the actor as a transparent vessel through which we see the thoughts and feelings of others. Humility is not a trait usually associated with actors. But there is something profoundly humble about their putting their bodies in the service of other minds.

That’s why Mr. Sands’s self-effacing mien as a narrator and commentator comes to seem so touching and so appropriate. He doesn’t want to get in Pinter’s way. My favorite moment in the show, by the way, isn’t from a poem, but when Mr. Sands, in Pinter’s voice as director, provides an invaluable demonstration.

“This is a beat. This is a pause. This is a silence.” Those are the words Pinter said. But you have to hear Mr. Sands saying them, at staggered intervals, to feel anew just how vibrant Pinter’s voice is, even when it is not speaking.